AFa340-300E
Topic Author
Posts: 2115
Joined: Tue May 18, 1999 3:49 am

767 Main Landing Gear

Thu Nov 09, 2000 5:43 am

Hello,

I have noticed many aircraft have the rear part of their main landing boggies going down for the landing, so that only two wheels touch down, and then the rest of the boggy (two or four other wheels according to the aircraft type).

But for the 767, this seems to be the opposite (front part first, then the rest). Any reason behind this please?


Click for large version
Click here for full size photo!

Photo © Felix Sieder



Thank you,

Best regards,
Alain Mengus
 
Guest

RE: 767 Main Landing Gear

Thu Nov 09, 2000 5:47 am

Do a search for "767 landing gear". You should find your answer there as this topic has been previously discussed.
 
AFa340-300E
Topic Author
Posts: 2115
Joined: Tue May 18, 1999 3:49 am

RE: 767 Main Landing Gear

Thu Nov 09, 2000 5:55 am

Hello,

Thank you Heavyjet.

Best regards,
Alain Mengus
 
Guest

RE: 767 Main Landing Gear

Fri Nov 10, 2000 12:51 am



As requested by AFa340-300E i performed a search into the 767 landing gear issue. i have to admit what i read was interesting. but the answer is easer than all the answers given. the 757 and 767 were designed to meet two different modes of flight. 757 = "short range" 767 = "long range". when designing for these differnet modes of flight different things are important. range, fuel consumption, cargo capacity, etc. due to placement of the wing, needed cargo space, the desire to have the smallest wheel well as possible and the dedsire to keep the aircraft from tilting when its on the ground, boeing designed the landing gear to move forward on retraction on the 767. where on the 757 it moves aft. so think about it, if the gear needs to move forward the forward tires need to be down so when it is retracted the "boggies" will be inline with the fuselage. the same is true if the landing gear retracts aft (757). as a point of interest the 707 gear moves straight in to the wheel wells so it has no tilt.

 
Guest

RE: 767 Main Landing Gear

Fri Nov 10, 2000 3:58 am

Im a little confused myself, dont you mean the gear will retract with the gear being retracted backwards, not fowards?
Thanks
 
Guest

RE: 767 Main Landing Gear

Fri Nov 10, 2000 4:00 am

Forget about my last post.
 
Guest

RE: 767 Main Landing Gear

Fri Nov 10, 2000 11:17 am

The 757, on landing and after the wheels leave the runway on takeoff, the aft MLG wheels have an aft tilt to them because there is no pressure on the tilt actuator. I forget the proper name of the actuator.

On gear retraction there is pressure to this actuator which straightens the wheels to a no tilt angle and this is how the wheels go in the hole (with no tilt).

On the 767 the wheels go in the hole just as you see in the pictures, with that FWD tilt.

OUT!
 
JT8DJET
Posts: 196
Joined: Fri Jul 07, 2000 12:28 am

RE: 767 Main Landing Gear

Fri Nov 10, 2000 1:24 pm

FYI,
Boeing calls it a Truck Positioner Actuator.
Airbus calls it a Pitch Damper.
Douglas calls it a Bogie Trim Cylinder.

Mech@lax, I have to disagree. The 757 gear goes into the hole with tilt.
 
Airgypsy
Posts: 130
Joined: Tue Nov 23, 1999 11:02 am

RE: 767 Main Landing Gear

Sat Nov 11, 2000 4:17 am

Fit to the wheel well gets the cookie. The bonus is that when the gear front truck touches down, the torque from spin up cushions the touchdown of the rear truck. The "normal" types have to contend with slamming because the rear truck torque amplifies front truck touchdown. Watch a film of a 747 and cringe at the sight of it.
Airgypsy
 
Guest

RE: 767 Main Landing Gear

Sun Nov 12, 2000 3:12 pm

When the 777 takes off, the gear tilts back, but when the retraction sequence starts, the bogeys tilt forward.

Who is online

Users browsing this forum: No registered users and 9 guests